1. Field of the Invention
Example embodiments relate to an organic light emitting diode (OLED) display and, more particularly, to an OLED display having a pixel initialized by a voltage supplied through a data line.
2. Description of the Related Art
An OLED display is a type of a flat panel display that uses an OLED to generate light. The light may be generated by combining electrons supplied by a cathode and holes supplied by an anode. Images may be realized on the OLED display by driving thin film transistors (TFT) formed at each pixel, which may supply the OLED with a driving current corresponding to a data signal. The OLED display may further include a plurality of pixels formed at an area where a plurality of scan lines, a plurality of emission control lines and a plurality of data lines intersect one another. Each pixel may include a pixel circuit for driving the pixel and may include the OLED to emit light according to the driving current of the pixel circuit. The pixel circuit may further include a driving switching element driven according to a data signal supplied by the data line, a storage element for storing a voltage between a source electrode of the driving switching element and a gate electrode and a plurality of switching elements.
The OLED may be driven through a pixel initializing period, a data writing period and a light emitting period. During the pixel initializing period, a previous data signal, which may be stored in the storage element, may be initialized to an initial voltage in response to a previous scan signal supplied through a previous scan line. During the data writing period, the voltage supplied by the data line in response to a current scan signal supplied through a current scan line may be stored in the storage element. During the light emitting period, the OLED may emit light according to the driving current that may flow through the driving switching element corresponding to the data signal stored in the storage element.
The pixel initializing period, however, may require an extra initial power source and an extra initial line (a line connected to an initial power source) to initialize the previous data signal stored in the storage element. The extra initial power source and the extra initial line may complicate the structure of the pixel circuit and may reduce an aperture ratio of the pixel. In addition, due to the increase number of data lines, there may be more integrated circuits to drive the OLED display and difficulty in maintaining a high resolution.
In order to manage the extra initial power source and the extra initial line, a demultiplexer (DeMux) may be used, which may have fewer output lines in the data driver. The DeMux may include a plurality of data supplying switching elements, which may be connected in common to the output line of the data driver. The respective data supplying switching elements may be coupled to a predetermined data line. Accordingly, the DeMux may supply the respective data line with the data signal in sequence by operating the data supplying switching elements.
The DeMux may further be driven by failing to initialize the previous data signal, in which case, a plurality of pixels may be coupled to each data line simultaneously by a current scan signal. Accordingly, the first pixel may be supplied with a current data signal and the next pixel may be supplied with a previous data signal. The previous data signal, however, may have a higher voltage level than the current data signal, which may reduce and/or prevent the supply of the current data signal to the respective pixel, because the driving switching element may be turned off. In addition, a time to charge the respective data line with the data signal may be decreased and the time during which the pixels are driven according to the scan signal may be decreased. As a result, the time to compensate a characteristic deviation of the driving switching element included in each pixel may be reduced and, thus, causing image quality to be non-uniform.